In cellular networks, such as networks complying with the UMTS (Universal Mobile Telecommunications System) standard, more and more traffic is due to data traffic.
Using EUL (enhanced uplink), capacity is increased and delay is reduced. EUL uses E-DCH (enhanced dedicated channel) for uplink transmission. E-DCH operates by deploying non-orthogonal transmissions, which has the effect of limiting the number of users that a cell can support in terms of performance and stability, due to the interference generated by the concurrent non-orthogonal transmissions.
There is thus a problem of how to increase throughput in such situations.
In order to control the interference, the radio base stations, also known as NodeBs, can implement a load estimation function. The load estimation function may predict the load of a user based in his SIR (signal to interference ratio) and granted ETFC (Enhanced Uplink Transport Format Combination) rate and feed that information back to a scheduler function in the NodeB. The scheduler function decides what grant rate to give to the user based on the load and the user requested rate.
However, capacity is always short and there is a perpetual need to further increase capacity and efficiency of transmission.